Submersible pool cleaner with integral rechargeable battery

Abstract

A submersible robotic pool cleaner is provided with an integral sealed rechargeable battery and an inductive charging assembly, a first portion of which is mounted in the pool cleaner housing and during the charging, receives a second separate portion that is connected by a cable to a conventional power source. The pump motor drive shaft is treated with a specialized anti-friction lubricant composition to minimize frictional energy losses where the shaft contacts the seal(s) and any shaft bearing(s), to maximize efficiency and minimize the power consumption of the pump motor assembly and permit the pool cleaner to completely traverse the surfaces to be cleaned within the fully-charged power capacity of the battery.

Description

FIELD OF THE INVENTIONThis invention relates to robotic, self-propelled submersible pool and tank cleaners.BACKGROUND OF THE INVENTIONConventional robotic pool cleaners are powered by electric drive motors and / or water pumps that receive power from a power cord or cable that is attached to a low-voltage power source outside of the pool. The use of a battery or batteries as a power source has also been proposed. For example, a rechargeable battery in a waterproof or water-resistant floating case having a power cable extending to the submerged pool cleaner has the advantage of eliminating or substantially reducing problems associated with twisting of the power cable which occurs with a remote stationary power supply unit as the pool cleaner traverses the bottom of the pool in its cleaning pattern.Although the inclusion of one or more batteries in the submersible pool cleaner housing has been proposed, the limitations of battery life and power consumption have prevented the realization...

AI Technical Summary

Benefits of technology

In accordance with the method and apparatus of the present invention, it has been found that the power requirements of the water pump assembly can be reduced from an average of about 4.5 amps to about 1.0 amp. This reduction in the pump motor power requirement is directly attributable to the reduction of frictional forces on the pump drive shaft by the seals and / or bearings. The effect of reducing the frictional forces is that a smaller battery having the necessary power storage capacity can be integrated into the construction and operation of the pool cleaner.

The reduction in friction losses is achieved by coating and treating the drive shaft of the pump assembly with a friction-reducing compound of the type that is commercially available for use in automotive crankcase applications.

In order to avoid any potential hazards, the battery is also connected to an inductive recharging circuit which itself is sealed and fitted with an inductive charging element. The employment of an inductive charging circuit eliminates the need for any exposed metallic conductors, which adds to the overall safety of the pool cleaner and its charging accessory. Although charging would not customarily be undertaken while the unit is in the water, in the event that the inductive charging element is mated in the charging position and the pool cleaner inadvertently pushed into the water, no shock hazard would arise.

In a further preferred embodiment of the invention, the impeller attached to the pump drive motor is in the form of a propeller which provides a relatively large volumetric water flow at a relatively low pressure and requires less power consumption than other well-known alternative types of impellers, such as centrifugal and turbine pumps.

Optionally, the drive motor shaft can be similarly treated with the anti-friction lubricant composition to further reduce the overall power consumption. However, the drive motor typically requires about one ampere-hour of power, which is a relatively low requirement.

Problems solved by technology

Although the inclusion of one or more batteries in the submersible pool cleaner housing has been proposed, the limitations of battery life and power consumption have prevented the realization of a practical commercial pool cleaner having an integral battery as the sole source of power that is required for cleaning a residential swimming pool.

As previously proposed, an integral battery lacks sufficient power to complete cleaning patterns known to have been disclosed or used by the prior art.

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